Commercial jets cruise at air speeds exceeding 500 mph. At takeoff air discharged from their engines has speeds exceeding 300 mph. The speed of this discharged air is greatest immediately behind the engines. At one end of the runway prior to take off pilots usually accelerate their engines to full power with their wheel brakes engaged in order to achieve maximum air speed at the other end of the runway in order to lift off. This engine accelerating position for take off is generally the same for all planes taking off. Immediately behind this accelerating position on the runway air is discharged at speeds exceeding 300 mph. This high velocity air exerts tremendous force and contains much inherent power.
Passengers and service personnel at an airport need to be protected from the direct force of air discharged from jet engines. Blast deflectors are used to protect individuals from this discharged air. Typically blast deflectors deflect laterally moving air upwardly so that individuals can safely pass behind these barriers. When an air recovery generator is used in conjunction with a blast deflector the discharged air is slowed as it imparts energy to the air recovery generator before it is finally diverted upwardly.